Heat equalizer

ABSTRACT

A heat equalizer includes a container structure, a material feed pipe, and a heating mechanism. The container structure includes an inner container and an outer container. In the outer container, a working fluid is held. Respective upper ends of the inner container and the outer container are joined to form a hollow portion between the inner container and the outer container. The material feed pipe extends from an outside of the container structure to the inner surface of the inner container. The heating mechanism is placed at the bottom of the outer container. At the bottom surface of the inner container, a plurality of protrusions protruding toward the inside of the inner container and depressions formed by the bottom surface depressed inward of the protrusions and capable of receiving the vaporized working fluid are formed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of and claims the benefit of priorityunder 35 U.S.C. §120 from U.S. Ser. No. 12/935,480 filed Sep. 29, 2010,the entire contents of which is incorporated herein by reference. U.S.Ser. No. 12/935,480 is a National Stage of PCT/JP08/57204 filed Apr. 11,2008 which was not published under PCT Article 21(2) in English.

TECHNICAL FIELD

The present invention relates to a heat equalizer, and particularly to aheat equalizer for heating a material that is a predetermined materialcarried in a container.

BACKGROUND ART

Regarding conventional organic EL (Electro-Luminescence) production, forexample, when a film is to be formed on a substrate using an organic ELmaterial in the form of powder, an evaporation apparatus for the organicEL material generally uses a heating system of heating the exterior of acontainer by means of a heater to sublimate or to melt and evaporate theorganic material in the container. A conventional apparatus used forsuch heat treatment is disclosed for example in Japanese PatentLaying-Open No. 2004-315898 (Patent Document 1).

FIG. 15 is a schematic configuration diagram for illustrating aconventional evaporation apparatus. FIG. 15 shows an evaporation sourcefor the evaporation apparatus that is characterized by that a container(crucible) 31 in which a material is held is heated by a heater 32placed on the outer periphery, and a heat equalizing lid 37 including anauxiliary heating unit 33 and a conduction heating unit 34 extendingcontinuously from the auxiliary heating unit is provided at an upperportion of container 31, separately from heater 32 on the outerperiphery, so that the temperature around an evaporation opening 35 atthe upper portion of container 31 is increased.

-   Patent Document 1: Japanese Patent Laying-Open No. 2004-315898

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The conventional evaporation apparatus shown in FIG. 15 has heatequalizing lid 37 provided at the upper portion of container (crucible)31 for the purpose of preventing evaporation opening 35 and therearoundlocated at the upper portion of container 31 from being clogged with avapor-deposition material 36 due to a temperature decrease aroundevaporation opening 35. Because this system, however, heats the outersurface of container 31 by means of heater 32, the inner surface ofcontainer 31 with which the vapor-deposition material is in contact hasa temperature distribution depending on the condition of contact withheater 32. A resultant problem is therefore that the vapor-depositionmaterial cannot be kept at a uniform temperature over the inner surfaceof container 31. For example, although Patent Document 1 showstemperature rise curves in connection with an embodiment, certainportions of container 31 do not uniformly increase in temperature and,even in a stable state, a temperature difference of approximately 30° C.still remains between the surface of container 31 and heat equalizinglid 37.

The conventional evaporation apparatus has another problem that it takessome time for the temperature of each portion of the apparatus to becomestable. For example, in an illustrated embodiment of Patent Document 1,it takes three or more hours for the temperature to become stable.

In the conventional evaporation apparatus, a melt of thevapor-deposition material has a temperature difference in the melt,resulting in a problem that the material is not uniformly evaporated.Specifically, while the material in contact with the wall surface of thecontainer is immediately heated to be evaporated, a melt of the materialin a central portion of the container which is located away from thewall surface of the container has its temperature increasing at a slowerrate and thus evaporation of the material is delayed. Further, due tothe influence of convection occurring to the melt of the material in thecontainer, the melt has a considerable temperature distribution. Thus,the temperature of the melt of the material cannot be controlled so thatthe temperature is uniform over the entire inner space of the container,and the amount of evaporation of the vapor-deposition material cannot becontrolled precisely, resulting in a problem that the apparatus is notsuitable for a precise film-forming process.

The present invention has been made to solve the above-describedproblems, and an object of the invention is to obtain a heat equalizerthat improves the uniformity of the temperature of a material to beheated in a container and thereby causes the material to be vaporizedstably.

Means for Solving the Problems

A heat equalizer according to an aspect of the present inventionincludes a container structure, a material feed pipe, and heating means.The container structure has an inner container and an outer container.In the outer container, a working fluid is held. Respective upper endsof the inner container and the outer container are joined to form ahollow portion between the inner container and the outer container. Thematerial feed pipe extends from an outside of the container structure toan inner surface of the inner container. The heating means is placed ata bottom of the outer container. At a bottom surface of the innercontainer, a plurality of protrusions protruding toward an inside of theinner container, and depressions formed by the bottom surface depressedinward of the protrusions and capable of receiving a vaporized workingfluid are formed.

A heat equalizer according to another aspect of the present inventionincludes a container structure, a material feed pipe, and heating means.The container structure has a heating block and an outer container. Theheating block has a flow path formed so that a material to be heatedflows in the flow path. In the outer container, a working fluid is held.Respective upper ends of the heating block and the outer container arejoined to form a hollow portion between the heating block and the outercontainer. The material feed pipe allows an outside of the containerstructure and the heating block to communicate with each other. Theheating means is placed at a bottom of the outer container. The flowpath for the material to be heated includes a first flow path connectedto the material feed pipe and extending in a horizontal direction, asecond flow path branching from the first flow path and extending in avertical direction, and an opening formed by the second flow pathopening at an upper surface of the container structure. At a bottomsurface of the heating block, a plurality of depressions formed by thebottom surface depressed toward an inside of the heating block andcapable of receiving a vaporized working fluid are formed. The secondflow path is placed between the depressions adjacent to each other.

A heat equalizer according to still another aspect of the presentinvention includes a container structure, heating means, and a pipechannel. The container structure includes an outer container. The outercontainer has a closed space which is formed in the outer container andin which a working fluid is held. The heating means is placed at abottom of the outer container. In the pipe channel, a material to beheated flows. The pipe channel includes a material feed pipe allowing anoutside and an inside of the container structure to communicate witheach other. The pipe channel also includes a main header pipe connectedto the material feed pipe and extending in a horizontal direction. Thepipe channel further includes branch header pipes branching from themain header pipe and extending in the horizontal direction. The pipechannel further includes a plurality of riser pipes branching from thebranch header pipes and opening at an upper surface of the containerstructure.

Effects of the Invention

According to the present invention, a gaseous working fluid is cooled tobe condensed on the inner wall surface of the depressions formed at theinner container, so that the inner container is heated, and thetemperature of the heated inner container is equalized. A material to beheated is heated while flowing in the inner container. Since thetemperature of the inner container is equalized, the material to beheated is heated on a heating surface with a uniform temperature. Theuniformity of the temperature of the material that has been heated to bevaporized can thus be improved. The amount of vaporization of thematerial to be heated can be controlled precisely. Accordingly, the heatequalizer applicable to a vapor deposition apparatus for forming a filmwith high precision can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an upper portion of a heat equalizer in a firstembodiment.

FIG. 2 is a cross section of the heat equalizer along line II-II shownin FIG. 1.

FIG. 3 is a plan view of an upper portion of a heat equalizer in asecond embodiment.

FIG. 4 is a plan view of an upper portion of a heat equalizer in a thirdembodiment.

FIG. 5 is a cross section of the heat equalizer along line V-V shown inFIG. 4.

FIG. 6 is a plan view of an upper portion of a heat equalizer in afourth embodiment.

FIG. 7 is a cross section of the heat equalizer along line VII-VII shownin FIG. 6.

FIG. 8 is a plan view of an upper portion of a heat equalizer in a fifthembodiment.

FIG. 9 is a cross section of the heat equalizer along line IX-IX shownin FIG. 8.

FIG. 10 is a cross section of a heat equalizer in a sixth embodiment.

FIG. 11 is a cross section of a heat equalizer in a seventh embodiment.

FIG. 12 is a cross section of a heat equalizer in an eighth embodiment.

FIG. 13 is a cross section of a heat equalizer in a ninth embodiment.

FIG. 14 is a cross section of a heat equalizer in a tenth embodiment.

FIG. 15 is a schematic configuration diagram for illustrating aconventional evaporation apparatus.

DESCRIPTION OF THE REFERENCE SIGNS

1 outer container; 2 inner container; 3 flange; 4 hollow portion; 5working fluid; 6 heating means; 7 vapor bubble; 8, 9, 13 arrow; 10, 14protrusion; 11, 15, 20, 21 depression; 12 material feed pipe; 16 heatingblock; 17 main header pipe; 18 branch header pipe; 19 riser pipe; 19 aopening; 22 fin body; 23 boiling promoter; 24 heater housing tube; 25heater; 26 heat generating portion; 27 fin body; 28 boiling promoter

BEST MODES FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will hereinafter be described basedon the drawings. In the following drawings, the same or correspondingparts are denoted by the same reference characters, and a descriptionthereof will not be repeated.

It should be noted that each component in the embodiments describedbelow is not necessarily requisite to the present invention unlessotherwise noted. Further, the number, quantity or the like specified inthe following embodiments is only by way of illustration unlessotherwise noted, and the scope of the present invention is notnecessarily limited to the specified number, quantity or the like.

First Embodiment

FIG. 1 is a plan view of an upper portion of a heat equalizer in a firstembodiment. FIG. 2 is a cross section of the heat equalizer along lineII-II shown in FIG. 1. In the following embodiments, “horizontaldirection” refers to the lateral direction in cross sections of the heatequalizer, and “vertical direction” refers to the top-bottom directionin these cross sections.

As shown in FIGS. 1 and 2, the heat equalizer includes an outercontainer 1 and an inner container 2. Outer container 1 is placed tosurround the periphery of inner container 2. The heat equalizer alsoincludes a flange 3. Outer container 1 and inner container 2 haverespective upper ends joined to flange 3 to form a container structurehaving a hollow portion 4 that is a closed space formed between innercontainer 2 and outer container 1.

At a bottom surface of inner container 2, a plurality of protrusions 10protruding toward the inside of inner container 2 are formed.Protrusions 10 are formed to protrude upward from the bottom surface ofinner container 2. As shown in FIG. 1, protrusions 10 are each formed sothat the shape in plan view is substantially a square, and are arrangedso that a plurality of columns of square protrusions and a plurality ofrows of square protrusions are disposed on the bottom surface of innercontainer 2. In FIG. 1, in a gap between protrusions 10 adjacent to eachother, the bottom surface of inner container 2 is exposed.

At the bottom surface of inner container 2, depressions 11 are formed bythe bottom surface depressed inward of protrusions 10. Depressions 11formed in a plurality of protrusions 10 are each an opening having itslower end open toward hollow portion 4 and having its upper end closed.Namely, depression 11 is a blind hole without extending through to theother side. The deepest portion of the blind hole shape of depression 11is the upper end of depression 11. Depression 11 is a circular holehaving a circular cross section along the radial direction of the hole,and also a linear hole extending linearly in its depth direction. Thedepth direction of depression 11 is along the vertical direction.

In hollow portion 4, a working fluid 5 that is a liquid working fluid isheld. The working fluid is a heat medium used for transferring heatbetween heating means, which serves as a heat source, and innercontainer 2, so as to heat inner container 2 and thereby control thetemperature so that the temperature is set at a target temperature.Working fluid 5 is selected in consideration of thermal properties andthe operating pressure (vapor pressure) at a temperature in use. Ingeneral, water is used as the working fluid for a temperature range ofapproximately not more than 200° C., and an organic heat medium of ahigh boiling point such as Dowtherm® A and naphthalene is used as theworking fluid for a high temperature range of approximately higher than200° C. and not more than 400° C.

Working fluid 5 is held in hollow portion 4 after hollow portion 4 isevacuated of air. Therefore, in hollow portion 4, a gaseous workingfluid is present that is vaporized working fluid 5. Since hollow portion4 is formed to separate outer container 1 and inner container 2 fromeach other, dissipation of heat from inner container 2 to the outside ofthe heat equalizer is substantially prevented.

At the bottom of outer container 1, heating means 6 for heating workingfluid 5 is placed. Heating means 6 is attached to the lower surface ofouter container 1 so that they are in thermal contact with each other.Heating means 6 is in thermal contact with the outer surface of outercontainer 1. Namely, the heat generated by heating means 6 can besufficiently and efficiently transferred to working fluid 5 via thebottom of outer container 1.

The heat equalizer also includes a material feed pipe 12 that allows theoutside and the inside of the container structure to communicate witheach other. Material feed pipe 12 is inserted from the outside of thecontainer structure, joined to one side of inner container 2 andextended to the inner surface of inner container 2. Material feed pipe12 is connected to the bottom of inner container 2. A material to beheated, which is a material to be heated and vaporized by this heatequalizer, flows in material feed pipe 12 placed to extend throughrespective sides of outer container 1 and inner container 2, and is fedto the bottom portion of the inner side surface of inner container 2 inthe heat equalizer. Depression 11 is formed so that the deepest portionof depression 11 is located at a higher level relative to the bottomportion of inner container 2 at which material feed pipe 12 is connectedto inner container 2.

In order for the material to be heated to pass through tubular materialfeed pipe 12, the material to be heated has to be a fluid. In the casewhere the material to be vaporized is solid at normal temperature, thefluidity of the material can be improved by, for example, heating andthereby melting the material, or grinding the material into powder andmixing the powder with a liquid to form a slurry, so as to allow thematerial to pass through the inside of material feed pipe 12.

An operation of the heat equalizer will now be described. In the heatequalizer of the first embodiment configured in the above-describedmanner, heating means 6 installed under outer container 1 generates heatand thereby heats outer container 1. As outer container 1 is heated,working fluid 5 is heated that is retained in a working fluid retainingportion at the bottom of the container structure, namely retained in thebottom portion of hollow portion 4 formed between outer container 1 andinner container 2. An arrow 8 of the broken line indicates the flow ofthe working fluid in the gaseous state, and an arrow 9 of the solid lineindicates the flow of the working fluid in the liquid state.

As working fluid 5 is heated to be evaporated, vapor bubbles 7 aregenerated in working fluid 5. A part of the working fluid that has beenheated to be evaporated into the gaseous state by heating means 6 movesfrom the liquid surface of working fluid 5 to the outer surface of innercontainer 2 as indicated by broken-line arrow 8. The gaseous workingfluid having moved to the outside of the side surface of inner container2 transfers heat to the outer surface of inner container 2, and isaccordingly cooled and condensed into the liquid state. The outer sidesurface of inner container 2 is a condensation surface on which thegaseous working fluid is condensed. The working fluid having beencondensed into the liquid state spontaneously flows back to the workingfluid retaining portion at the bottom of the container structure asindicated by solid-line arrow 9.

Further, a part of the gaseous working fluid moves from the liquidsurface of working fluid 5 to the inside of depression 11 as indicatedby broken-line arrow 8. Depression 11 is formed to be able to accept thevaporized working fluid. The gaseous working fluid having moved intodepression 11 transfers heat to the inner wall surface of depression 11,and is accordingly cooled and condensed into the liquid state. The innerwall surface of depression 11 is a condensation surface on which thegaseous working fluid is condensed. The working fluid having beencondensed into the liquid state also spontaneously flows back to theworking fluid retaining portion at the bottom of the container structureas indicated by solid-line arrow 9.

In this way, the outer surface of inner container 2 and the innersurface of depressions 11 formed at the bottom surface of innercontainer 2 are heated through the evaporation and condensation of theworking fluid. This heating causes the side surface portion of innercontainer 2 and the surface of protrusions 10 to be heated.

As for the material to be heated that is a predetermined material, thematerial proceeds as indicated by an arrow 13 from the outside of thecontainer structure through material feed pipe 12 to the bottom portionof inner container 2, and the material is fed to the gap betweenprotrusions 10 formed in inner container 2. While passing in innercontainer 2, the material to be heated is heated from the side portionof inner container 2 and the side portion of protrusions 10. Namely, thematerial to be heated that is supplied through material feed pipe 12into inner container 2 is heated through heat exchange with workingfluid 5 heated to be evaporated into the gaseous state by heating means6.

Over an almost entire bottom surface of inner container 2, a pluralityof protrusions 10 are formed. Therefore, the area of the heat transfersurface, which is a portion of the surface of inner container 2 andwhich receives heat from the evaporated working fluid and is capable oftransferring the heat to the material to be heated, is increased. Thearea of the heat transfer surface is increased and the material to beheated flowing in inner container 2 receives heat from the increasedheat transfer surface, and therefore, a temperature difference isprevented from being generated in the material to be heated that flowsin inner container 2 to be heated. Namely, the uniformity of thetemperature of the material to be heated can be improved.

The gap between the wall surfaces of protrusions 10 that is a gapbetween two protrusions 10 adjacent to each other is formed to have adimension of approximately 2 to 3 mm. Therefore, convection of a melt ofthe material to be heated does not occur in inner container 2 and thereis no temperature unevenness of the material to be heated in innercontainer 2, and thus the temperature of the material to be heated thatis held in the gap between the wall surfaces can further be equalized.

In inner container 2, when the material to be heated is heated to atemperature close to the boiling point, the material to be heated isevaporated into the gaseous state. The gaseous material to be heatedflows upward in the gap between protrusions 10 to the outside of innercontainer 2. Thus, the gaseous material to be heated that has asuppressed temperature distribution and an equalized temperature can beobtained.

As heretofore described, the heat equalizer in the first embodimentincludes the container structure, material feed pipe 12, and heatingmeans 6. The container structure has inner container 2 and outercontainer 1. In outer container 1, the working fluid is held. Respectiveupper ends of inner container 2 and outer container 1 are joined to formhollow portion 4 between inner container 2 and outer container 1.Material feed pipe 12 extends from the outside of the containerstructure to the inner surface of inner container 2. Heating means 6 isplaced at the bottom of outer container 1. At the bottom surface ofinner container 2, a plurality of protrusions 10 protruding toward theinside of inner container 2, and depressions 11 formed by the bottomsurface depressed inward of protrusions 10 and capable of receiving thevaporized working fluid are formed.

Thus, condensation of the working fluid on the outer surface of innercontainer 2 and on the inner wall surface of depressions 11 provided toinner container 2 causes inner container 2 to be heated, and theuniformity of the temperature of heated inner container 2 is improved.The material to be heated that is heated while flowing in innercontainer 2 is heated on a heating surface of the uniform temperature,namely the inner side surface of inner container 2 and on the surface ofprotrusions 10, and thus the whole material to be heated can beuniformly vaporized. The temperature of the material having been heatedcan therefore be equalized. Further, the gap between protrusions 10 ismade small, so that convection of the melt of the material to be heatedthat passes in inner container 2 can be suppressed, and the uniformityof the temperature of the material to be heated that has been heated andvaporized can further be improved.

Depression 11 is formed so that the deepest portion of depression 11 islocated higher than the position where material feed pipe 12 isconnected to inner container 2. Typically, material feed pipe 12 isconnected to the bottom portion of inner container 2. Thus, the materialto be heated that is fed from material feed pipe 12 can be retained ininner container 2 for a longer period of time, and the material to beheated passes along the surface of protrusions 10 over a greaterdistance along the vertical direction. The material to be heatedtherefore can receive heat from the larger heat transfer surface, andgeneration of a temperature difference in the material to be heated isfurther suppressed, and the uniformity of the temperature of thematerial to be heated can further be improved.

In this way, the temperature of the heat transfer surface of innercontainer 2 that heats the material to be heated can be managed so thatthe distribution of the temperature is within ±1° C. The temperature ofthe material to be heated can be precisely controlled and the amount ofvaporization of the material to be heated can be controlled with highprecision. Thus, an evaporation source applicable to a vapor depositionapparatus suitable for a high-precision film forming process can beobtained.

Further, the material to be heated is spread and heated in the gapsbetween a large number of protrusions 10 formed at inner container 2,and the area of the heat transfer surface is therefore increased and thematerial to be heated can be heated over the heat transfer surface ofthe large area. Therefore, the efficiency in heating the material to beheated is enhanced and the thermal response when the temperature isincreased is considerably improved. In addition, the thermal energy forincreasing the temperature can be minimized. Thus, the heat equalizerwith improved heat transfer efficiency and suitable for energy savingcan be obtained.

Second Embodiment

FIG. 3 is a plan view of an upper portion of a heat equalizer in asecond embodiment. The heat equalizer in the second embodiment differsfrom the heat equalizer in the first embodiment in that protrusions anddepressions formed at the bottom surface of inner container 2 are shapedin the manner as shown in FIG. 3.

Specifically, while the first embodiment has been described in which alarge number of protrusions 10 are formed to extend upward from thebottom surface of inner container 2, a plurality of protrusions 14having a rectangular shape in plan view may be formed to extend upwardfrom the bottom surface of inner container 2 as shown in FIG. 3, anddepressions 15 each having the lower end communicating with hollowportion 4 may be provided in this protrusion 14. Namely, as shown inFIG. 3, protrusions 14 are each formed in the shape of a rectangularparallelepiped and are arranged in parallel to each other. Depressions15 are each formed in the shape of a groove extending along thelongitudinal direction of the shape of the rectangular parallelepiped ofprotrusion 14.

In the first embodiment, while the material to be heated passes in thegaps between many protrusions 10, the flow of the material may stagnatearound protrusions 10 and the material may be retained there in somecases. In contrast, in the configuration of the second embodiment, thematerial to be heated that is fed to the bottom portion of innercontainer 2 can smoothly flow along the wall surface of protrusions 14and in one direction between protrusions 14. The material to be heatedcan therefore be uniformly heated and evaporated along the direction ofthe flow of the material, and the amount of evaporation can becontrolled with higher precision. As compared with the case where alarge number of protrusions 10 are disposed, the number of protrusions14 can be decreased, the number of process steps can be reduced, and theheat equalizer of low cost can be obtained.

Third Embodiment

FIG. 4 is a plan view of an upper portion of a heat equalizer in a thirdembodiment. FIG. 5 is a cross section of the heat equalizer along lineV-V shown in FIG. 4. As shown in FIGS. 4 and 5, the heat equalizer inthe third embodiment includes an outer container 1 and a heating block16. Outer container 1 is placed to surround the periphery of heatingblock 16.

The heat equalizer includes a flange 3. Outer container 1 and heatingblock 16 have respective upper ends joined to flange 3 to form acontainer structure having a hollow portion 4 that is a closed spaceformed between heating block 16 and outer container 1. As shown in FIG.5, heating block 16 is provided at a central opening of flange 3, andthe periphery of heating block 16 is joined to flange 3 to allow heatingblock 16 to hang in outer container 1.

Like the first embodiment, a working fluid 5 is held in hollow portion4, and working fluid 5 is held in hollow portion 4 after hollow portion4 is evacuated of air. At the bottom of outer container 1, heating means6 for heating working fluid 5 is placed. The heat equalizer includes amaterial feed pipe 12 that allows the outside of the container structureand heating block 16 to communicate with each other.

In heating block 16, a main header pipe 17 connected to material feedpipe 12 and extending in the horizontal direction, a plurality of branchheader pipes 18 branching from main header pipe 17 and extending in thehorizontal direction, and a plurality of riser pipes 19 branching frombranch header pipes 18 and extending in the vertical direction areprocessed and formed. Main header pipe 17, branch header pipes 18, andriser pipes 19 are each a hole formed in heating block 16. The upper endof riser pipe 19 is opened at the upper surface of heating block 16 toform an opening 19 a. Main header pipe 17, branch header pipes 18, riserpipes 19, and openings 19 a are included in a flow path in which amaterial to be heated flows.

At the bottom surface of heating block 16, a plurality of depressions 20are formed by the bottom surface depressed toward the inside of heatingblock 16. Depressions 20 are each an opening having the lower end opento hollow portion 4 and having the upper end closed. Namely, depression20 is a blind hole without extending through to the other side. Thedeepest portion of the blind hole shape of depression 20 is the upperend of depression 20. Depression 20 is a circular hole having a circularcross section along the radial direction of the hole, and also a linearhole extending linearly in its depth direction. The depth direction ofdepression 20 is along the vertical direction.

Depressions 20 are formed from the lower surface toward the uppersurface of heating block 16 at respective positions that do notinterfere with riser pipes 19. Depressions 20 are formed to extendbetween riser pipes 19. Depressions 20 are formed between riser pipes 19and separated from the flow path for a material to be heated. As shownin FIG. 4, depressions 20 adjacent to each other are formed respectivelyon the opposite sides of riser pipe 19 to sandwich riser pipe 19.Between depressions 20 adjacent to each other, riser pipe 19 is placed.

In the heat equalizer of the third embodiment configured in theabove-described manner, when outer container 1 is heated by heatgenerated by heating means 6, working fluid 5 retained in a workingfluid retaining portion at the bottom of the container structure isheated. A part of the working fluid that is heated and evaporated intothe gaseous state by heating means 6 moves to the outer surface ofheating block 16. Further, a part of the gaseous working fluid movesfrom the liquid surface of working fluid 5 to the inside of depressions20. Depressions 20 are formed to be able to accept the vaporized workingfluid. The gaseous working fluid transfers heat to the outer surface ofheating block 16 as well as the inner wall surface of depressions 20 andis accordingly cooled and condensed into the liquid state. The outersurface of heating block 16 and the inner wall surface of depressions 20are condensation surfaces on which the gaseous working fluid iscondensed. The working fluid condensed into the liquid statespontaneously flows back to the working fluid retaining portion at thebottom of the container structure.

In this way, the outer surface of heating block 16 and the inner surfaceof depressions 20 formed at the bottom surface of heating block 16 areheated through the evaporation and condensation of the working fluid.The outer surface of heating block 16 and the depressions 20 areincluded in a condensation path in which the working fluid having beenheated and evaporated by heating means 6 is cooled and condensed.

As for the material to be heated that is a predetermined material, thematerial proceeds as indicated by an arrow 13 from the outside of thecontainer structure through material feed pipe 12 to heating block 16,and is successively conveyed by pressure to riser pipes 19 through mainheader pipe 17 and then branch header pipes 18 formed in heating block16. While passing in heating block 16, the material to be heated isheated from the side surface portion of heating block 16 and the wallsurface of depressions 20 provided in heating block 16. Namely, thematerial to be heated that is supplied through material feed pipe 12into heating block 16 is heated through heat exchange with the gaseousworking fluid that is working fluid 5 heated and evaporated into thegaseous state by heating means 6.

At this time, riser pipe 19 is formed between two depressions 20adjacent to each other. While the material to be heated flows in riserpipe 19, heat is transferred to the material from these depressions 20formed respectively on the opposite sides of the riser pipe.

To the material to be heated that flows in the flow path formed inheating block 16, heat is transferred from two depressions 20 formed tosandwich the flow path. The material to be heated that is flowing in theflow path is heated from two directions opposite to each other. Becausethe material to be heated receives heat from multiple directions,generation of a temperature difference in the material to be heated thatflows in the flow path is suppressed. Namely, the uniformity of thetemperature of the material to be heated can be improved.

The inner diameters of main header pipe 17, branch header pipe 18, andriser pipe 19 are each selected so that the flow rate of the material tobe heated in main header pipe 17 is sufficiently lower than the flowrate of the material to be heated in branch header pipe 18 and so thatthe flow rate of the material to be heated in branch header pipe 18 issufficiently lower than the flow rate of the material to be heated inriser pipe 19. Therefore, the material to be heated that flows out ofmain header pipe 17 equally enters a plurality of branch header pipes 18and likewise equally enters a plurality of riser pipes 19. Namely, thematerial to be heated moves in a constant flow state through apredetermined flow path, and therefore, it does not occur that thematerial to be heated stays at a specific part in the flow path to causerespective temperature histories at respective positions in the flowpath to be different from each other. Accordingly, the temperaturehistory of the material to be heated can be equalized and thetemperature uniformity of the material after heated can be improved.

When riser pipe 19 is formed of a pipe having a small inner diameter ofapproximately 2 to 3 mm, convection of the melt of the material to beheated does not occur in riser pipe 19, and no temperature unevenness isgenerated in the material to be heated in riser pipe 19. Therefore, thetemperature of the material to be heated can be further equalized.

In heating block 16, when the material to be heated is heated to atemperature close to the boiling point, the material to be heated isevaporated into the gaseous state. The gaseous material to be heatedflows through opening 19 a to the outside of heating block 16. Thus, thegaseous material to be heated that has a suppressed temperaturedistribution and an equalized temperature can be obtained.

As heretofore described, the heat equalizer in the third embodimentincludes the container structure, material feed pipe 12, and heatingmeans 6. The container structure has heating block 16 and outercontainer 1. In heating block 16, a flow path in which the material tobe heated flows is formed. In outer container 1, a working fluid isheld. Heating block 16 and outer container 1 have respective upper endsjoined to form hollow portion 4 between heating block 16 and outercontainer 1.

Material feed pipe 12 allows the outside of the container structure andheating block 16 to communicate with each other. Heating means 6 isplaced at the bottom of outer container 1. The flow path of the materialto be heated includes main header pipe 17 and branch header pipes 18connected to material feed pipe 12 and extending in the horizontaldirection to serve as a first flow path, riser pipes 19 branching fromthe first flow path and extending in the vertical direction to serve asa second flow path, and openings 19 a formed by the second flow pathopening at the upper surface of the container structure. At the bottomsurface of heating block 16, a plurality of depressions 20 capable ofreceiving the vaporized working fluid is formed by the bottom surfacedepressed toward the inside of heating block 16. Between depressions 20adjacent to each other, riser pipe 19 is placed.

In this way, heating block 16 is heated through condensation of theworking fluid on the outer surface of heating block 16 and on the innerwall surface of depressions 20 provided in heating block 16, and theuniformity of the temperature of heating block 16 having been heated isimproved. The material to be heated that is heated while flowing in theflow path formed in heating block 16 is heated on the heating surface ofa uniform temperature, namely the inner wall surface of main header pipe17, branch header pipe 18 and riser pipe 19, and thus the whole materialto be heated can be uniformly vaporized. The temperature of the materialto be heated having been heated can therefore be equalized.

Further, the flow path is formed so that the material to be heatedcontinuously flows to opening 19 a from the connecting portion betweenthe material feed pipe 12 and main header pipe 17, and the material tobe heated is successively conveyed from main header pipe 17 throughbranch header pipe 18 to riser pipe 19 to be heated. Thus, the materialto be heated does not partially stay at a part of the flow path, thematerial to be heated constantly flows, and the uniformity of theheating history of the material to be heated can be improved.

Furthermore, because riser pipe 19 has a small diameter, convection ofthe melt of the material to be heated that passes in riser pipe 19 canbe suppressed, and the uniformity of the temperature of the material tobe heated that has been heated and vaporized can further be improved. Alarge number of riser pipes 19 each having a small diameter ofapproximately 2 to 3 mm can be provided to increase the area of thesurface transferring heat to the material to be heated. The material tobe heated can thus be heated with the heat transfer surface of the largearea. The efficiency in heating the material to be heated can further beimproved.

The material to be heated is spread and heated in the flow path that isa network of the small diameter pipe. Accordingly, the area of the heattransfer surface is increased, and the material to be heated can beheated by means of the heat transfer surface of the large area.Therefore, the efficiency in heating the material to be heated isenhanced and the thermal response when the temperature is increased isconsiderably improved. In addition, the thermal energy for increasingthe temperature can be minimized. Thus, the heat equalizer with improvedheat transfer efficiency and suitable for energy saving can be obtained.

Fourth Embodiment

FIG. 6 is a plan view of an upper portion of a heat equalizer in afourth embodiment. FIG. 7 is a cross section of the heat equalizer alongline VII-VII shown in FIG. 6. The heat equalizer in the fourthembodiment differs from the heat equalizer in the third embodiment inthat the depression formed at the bottom surface of heating block 16 isshaped in the manner as shown in FIGS. 6 and 7.

Specifically, the third embodiment has been illustrated in which aplurality of depressions 20 in the shape of a circular hole and havingthe lower end communicating with hollow portion 4 are processed at thebottom surface of heating block 16, so that the depressions do notinterfere with riser pipes 19. Instead, as shown in FIGS. 6 and 7, adepression 21 having the lower end communicating with hollow portion 4and having the shape of a blind groove may be provided from the lowersurface side of heating block 16 to the inside thereof, so that thedepression does not interfere with riser pipes 19. In this way, thesurface area of depressions 21 on which the gaseous working fluid iscondensed can be increased, the amount of heat for heating the materialto be heated that flows in riser pipes 19 is increased and the heatcapacity of heating block 16 can be decreased. Thus, the efficiency inheating the material to be heated can further be improved.

Fifth Embodiment

FIG. 8 is a plan view of an upper portion of a heat equalizer in a fifthembodiment. FIG. 9 is a cross section of the heat equalizer along lineIX-IX shown in FIG. 8. As shown in FIGS. 8 and 9, the heat equalizer inthe fifth embodiment includes an outer container 1 and a pipe channel inwhich a material to be heated flows. Outer container 1 is placed tosurround the periphery of the pipe channel. The heat equalizer includesa flange 3. Outer container 1 has an upper end joined to flange 3 toform a container structure having a hollow portion 4 that is a closedspace formed in outer container 1. The pipe channel is placed in hollowportion 4 formed in outer container 1.

Like the first embodiment, a working fluid 5 is held in hollow portion4, and working fluid 5 is held in hollow portion 4 after hollow portion4 is evacuated of air. At the bottom of outer container 1, heating means6 for heating working fluid 5 is placed. The heat equalizer includes amaterial feed pipe 12 that allows the outside and the inside of thecontainer structure to communicate with each other.

In hollow portion 4, a main header pipe 17 connected to one end ofmaterial feed pipe 12 and extending in the horizontal direction, aplurality of branch header pipes 18 branching from main header pipe 17and extending in the horizontal direction, and a plurality of riserpipes 19 branching from branch header pipes 18 and extending in thevertical direction are processed and formed. Main header pipe 17, branchheader pipes 18, and riser pipes 19 are each a tubular member. The upperend of riser pipe 19 is opened at the upper surface of flange 3 to forman opening 19 a. The upper end portion of riser pipe 19 is connected toflange 3 to be opened to the outside of the container structure.Material feed pipe 12, main header pipe 17, branch header pipes 18,riser pipes 19, and openings 19 a are included in the pipe channel inwhich the material to be heated flows.

In the heat equalizer of the fifth embodiment configured in theabove-described manner, when outer container 1 is heated by heatgenerated by heating means 6, working fluid 5 retained in a workingfluid retaining portion at the bottom of the container structure isheated. A part of the working fluid that is heated and evaporated intothe gaseous state by heating means 6 moves to the surface of the pipechannel. The gaseous working fluid transfers heat to the surface of thepipe channel and is accordingly cooled and condensed into the liquidstate. The surface of the pipe channel is a condensation surface onwhich the gaseous working fluid is condensed. The working fluidcondensed into the liquid state spontaneously flows back to the workingfluid retaining portion at the bottom of the container structure. Inthis way, the surface of the pipe channel is heated through evaporationand condensation of the working fluid.

As for the material to be heated that is a predetermined material, thematerial proceeds as indicated by an arrow 13 from the outside of thecontainer structure through material feed pipe 12 to the pipe channel inhollow portion 4, and is successively conveyed by pressure to riserpipes 19 through main header pipe 17 and then branch header pipes 18.While passing in the pipe channel, the material to be heated is heatedfrom the wall surface of the pipe channel. Namely, the material to beheated that is supplied through material feed pipe 12 into outercontainer 1 is heated through heat exchange with the gaseous workingfluid that is working fluid 5 heated and evaporated into the gaseousstate by heating means 6.

The inner diameters of main header pipe 17, branch header pipe 18, andriser pipe 19 are each selected so that the flow rate of the material tobe heated in main header pipe 17 is sufficiently lower than the flowrate of the material to be heated in branch header pipe 18 and so thatthe flow rate of the material to be heated in branch header pipe 18 issufficiently lower than the flow rate of the material to be heated inriser pipe 19. Therefore, the material to be heated that flows out ofmain header pipe 17 equally enters a plurality of branch header pipes 18and likewise equally enters a plurality of riser pipes 19. Namely, thematerial to be heated moves in a constant flow state through apredetermined flow path, and therefore, it does not occur that thematerial to be heated stays at a specific part in the flow path to causerespective temperature histories at respective positions in the flowpath to be different from each other. Accordingly, the temperaturehistory of the material to be heated can be equalized and thetemperature uniformity of the material after heated can be improved.

When riser pipe 19 is formed of a pipe having a small inner diameter ofapproximately 2 to 3 mm, convection of the melt of the material to beheated does not occur in riser pipe 19, and no temperature unevenness isgenerated in the material to be heated in riser pipe 19. Therefore, thetemperature of the material to be heated can be further equalized.

In the pipe channel, when the material to be heated is heated to atemperature close to the boiling point, the material to be heated isevaporated into the gaseous state. The gaseous material to be heatedflows through opening 19 a to the outside of the container structure.Thus, the gaseous material to be heated that has a suppressedtemperature distribution and an equalized temperature can be obtained.

As heretofore described, the heat equalizer in the fifth embodimentincludes the container structure, heating means 6, and the pipe channel.The container structure includes outer container 1 having a closed spacewhich is formed in the container structure and in which a working fluidis held. Heating means 6 is placed at the bottom of outer container 1.In the pipe channel, a material to be heated flows. The pipe channelincludes material feed pipe 12 allowing the outside and the inside ofthe container structure to communicate with each other. The pipe channelalso includes main header pipe 17 connected to material feed pipe 12 andextending in the horizontal direction. The pipe channel further includesbranch header pipes 18 branching from main header pipe 17 and extendingin the horizontal direction. The pipe channel further includes aplurality of riser pipes 19 branching from branch header pipes 18 andopening at the upper surface of the container structure.

Thus, the pipe channel which includes main header pipe 17, branch headerpipes 18, and riser pipes 19 and in which the material to be heatedflows is entirely brought into contact directly with the working fluidhaving been heated and evaporated into the gaseous state. Therefore, thewhole pipe channel is efficiently heated through condensation of theworking fluid, so that the efficiency in heating the material to beheated can be improved remarkably. Further, the structure of the heatequalizer can be simplified remarkably.

The pipe channel is heated through condensation of the working fluid onthe outer surface of the pipe channel, and the uniformity of thetemperature of the pipe channel having been heated is improved. Thematerial to be heated that is heated while flowing in the pipe channelis heated on the heating surface of a uniform temperature, namely theinner wall surface of main header pipe 17, branch header pipe 18 andriser pipe 19, and thus the whole material to be heated can be uniformlyvaporized. The temperature of the material to be heated having beenheated can therefore be equalized.

Further, the flow path is formed so that the material to be heatedcontinuously flows to opening 19 a from the connecting portion betweenmaterial feed pipe 12 and main header pipe 17, and the material to beheated is successively conveyed from main header pipe 17 through branchheader pipe 18 to riser pipe 19 to be heated. Thus, the material to beheated does not partially stay at a part of the flow path, the materialto be heated constantly flows, and the uniformity of the heating historyof the material to be heated can be improved.

Furthermore, because riser pipe 19 has a small diameter, convection ofthe melt of the material to be heated that passes in riser pipe 19 canbe suppressed, and the uniformity of the temperature of the material tobe heated that has been heated and vaporized can further be improved. Alarge number of riser pipes 19 each having a small diameter ofapproximately 2 to 3 mm can be provided to increase the area of thesurface transferring heat to the material to be heated. The material tobe heated can thus be heated with the heat transfer surface of the largearea. The efficiency in heating the material to be heated can further beimproved.

The material to be heated is spread and heated in the pipe channelnetwork of a small diameter. Accordingly, the area of the heat transfersurface is increased, and the material to be heated can be heated bymeans of the heat transfer surface of the large area. Therefore, theefficiency in heating the material to be heated is enhanced and thethermal response when the temperature is increased is considerablyimproved. In addition, the thermal energy for increasing the temperaturecan be minimized. Thus, the heat equalizer with improved heat transferefficiency and suitable for energy saving can be obtained.

The inner surfaces of main header pipe 17, branch header pipes 18, andriser pipes 19 in which the material flows have to be polished forpreventing the material from attaching to the surfaces and forpretreatment prior to surface treatment, for example. In the case of theheat equalizer in the fifth embodiment, the flow path for the materialto be heated is a tubular body. Therefore, the pipe channel may beconfigured using a commercially available polished pipe so that theinner surface treatment can be dispensed with. Thus, the number ofprocess steps for the flow path of the material to be heated can beconsiderably reduced, and the heat equalizer of low cost can beobtained.

Sixth Embodiment

FIG. 10 is a cross section of a heat equalizer in a sixth embodiment.While the first to fifth embodiments above have been described in whichheating means 6 is placed under outer container 1, a fin body 22 may beprovided as shown in FIG. 10 on the inner surface of the bottom of outercontainer 1 that corresponds to the location where heating means 6 isattached.

In this way, the area on which working fluid 5 is evaporated can beextended, and therefore boiling of working fluid 5 is promoted and thethermal response of the heat equalizer can be improved. Further, theheat of heating means 6 is speedily transferred to working fluid 5 inouter container 1. Therefore, increase of the surface temperature ofouter container 1 is suppressed and, in the vicinity of heating means 6,overheating of outer container 1 can be prevented. In addition, theamount of heat dissipation from the container structure to theperipheral area is reduced. Accordingly, the energy-saving heatequalizer can be obtained.

Seventh Embodiment

FIG. 11 is a cross section of a heat equalizer in a seventh embodiment.While the sixth embodiment above has been described in which the heatequalizer has fin body 22 formed on the inner surface of the bottom ofouter container 1, a boiling promoter 23 may be placed on the innersurface of the bottom of outer container 1 as shown in FIG. 11.

This boiling promoter 23 is formed using, for example, metal mesh,sintered body of metal powder, or the like. Boiling promoter 23 enablesworking fluid 5 to boil efficiently. Therefore, the thermal response ofheat equalizer can further be improved, increase of the surfacetemperature of outer container 1 heated by heating means 6 can furtherbe suppressed, and the amount of heat dissipation from the containerstructure to the peripheral area is further reduced. Accordingly, theheat equalizer with improved energy saving can be obtained.

Eighth Embodiment

FIG. 12 is a cross section of a heat equalizer in an eighth embodiment.While the first to seventh embodiments above have been described inwhich heating means 6 is placed on the outer surface of the bottom ofouter container 1, one end of a heater housing tube 24 may be joined andsecured to a lower portion of outer container 1 and the other end ofheater housing tube 24 may be immersed in working fluid 5 in outercontainer 1 as shown in FIG. 12. As shown in FIG. 12, in the eighthembodiment, a heater 25 having a heat generating portion 26 is housed inheater housing tube 24, and heat generating portion 26 is placed awayfrom that one end of heater housing tube 24.

In this way, working fluid 5 can be heated directly by means of heaterhousing tube 24. Further, heat generating portion 26 of heater 25 islocated away from the joint portion between heater housing tube 24 andouter container 1, so that the influence of heat transfer from heater 25to outer container 1 can be lessened and thus heat dissipation fromouter container 1 to the surrounding area can be considerablysuppressed. Further, since working fluid 5 is evaporated speedily, thethermal response of the heat equalizer can be considerably improved.

Ninth Embodiment

FIG. 13 is a cross section of a heat equalizer in a ninth embodiment.While the eighth embodiment above has been described in which heaterhousing tube 24 is placed in outer container 1 for heating working fluid5, a fin body 27 may be formed on the outer surface of heater housingtube 24 as shown in FIG. 13.

In this way, heat is transferred more efficiently from heater 25 toworking fluid 5, and the working fluid is evaporated more speedily.Accordingly, the thermal response of the heat equalizer can further beimproved.

Tenth Embodiment

FIG. 14 is a cross section of a heat equalizer in a tenth embodiment.While the ninth embodiment above has been described in which heaterhousing tube 24 on which fin body 27 is formed is placed in outercontainer 1 for heating working fluid 5, a boiling promoter 28 may beformed on the outer surface of heater housing tube 24 as shown in FIG.14.

In this way, working fluid 5 is heated by heater 25 more efficiently,and working fluid 5 is still more speedily evaporated from the surfaceof boiling promoter 28. Therefore, the thermal response of the heatequalizer can further be improved.

While the series of embodiments above have been described in which thecontainer structure has a quadrilateral shape as seen in plan view, theshape of the container structure is not limited to the quadrilateral andmay alternatively be any polygon or circle.

For heating means 6, electrical heating, induction heating, hot waterheating, or vapor heating or the like may be used. The heating system isnot limited to a particular one.

Although material feed pipe 12 extends through a side of outer container1 to be connected to inner container 2 or main header pipe 17 in theexamples illustrated above, the passage of material feed pipe 12 is notlimited to a particular one. Material feed pipe 12 may extend from thelower surface of outer container 1 to reach main header pipe 17, or mayextend through a feed hole formed in flange 3 to reach main header pipe17. Material feed pipe 12 may extend along any passage.

As for the direction of extension of main header pipe 17, branch headerpipe 18, and riser pipe 19 included in the flow path for the material tobe heated, as well as depression 11 formed in inner container 2 anddepression 20 formed in heating block 16, the direction as described isdefined as horizontal direction or vertical direction. The directionalong which the flow path and the depressions extend, however, may notbe exactly parallel with the horizontal or vertical direction, and maybe inclined instead. Further, the flow path and the depressions are notlimited to linear pipe or linear pit, and may include a bent or curvedpipe or hole. Depressions 11, 20 each are not limited to a circular holehaving a circular cross section, and may have any shape which may forexample be rectangle hole.

While the embodiments of the present invention have been explained,respective features of the embodiments may be combined as appropriate.It should be construed that the embodiments disclosed herein are by wayof illustration in all respects, not by way of limitation. It isintended that the scope of the present invention is defined by claims,not by the above description of the embodiments, and includes allmodifications and variations equivalent in meaning and scope to theclaims.

INDUSTRIAL APPLICABILITY

The present invention is suitable for an evaporation source of anevaporation apparatus that heats a material which is a predeterminedmaterial carried in a container to melt and evaporate the material, sothat a film of the material to be vapor-deposited is formed on a surfaceof a substrate.

The invention claimed is:
 1. A heat equalizer comprising: a containerstructure including a heating block with a flow path formed so that amaterial to be heated flows in the flow path, and an outer container inwhich a working fluid is held, respective upper ends of said heatingblock and said outer container being joined to form a hollow portionbetween said heating block and said outer container; a material feedpipe allowing an outside of said container structure and said heatingblock to communicate with each other; and heating means placed at abottom of said outer container, wherein said flow path includes a firstflow path connected to said material feed pipe and extending in ahorizontal direction, a second flow path branching from said first flowpath and extending in a vertical direction, and an opening formed bysaid second flow path opening at an upper surface of said containerstructure, at a bottom surface of said heating block, a plurality ofdepressions formed by said bottom surface depressed toward an inside ofsaid heating block and capable of receiving a vaporized working fluidare formed, said second flow path is placed between said depressionsadjacent to each other, a heater housing tube having one end secured tosaid outer container and the other end immersed in the working fluid ofliquid state; and a heater housed in said heater housing tube and havinga heat generating portion, wherein said heat generating portion isplaced away from said one end of said heater housing tube that issecured to said outer container.
 2. The heat equalizer according toclaim 1, wherein said heating means is in thermal contact with an outersurface of said outer container.
 3. The heat equalizer according toclaim 1, wherein a fin body is formed at an inner surface of the bottomof said outer container.
 4. The heat equalizer according to claim 1,wherein a boiling promoter is placed at an inner surface of the bottomof said outer container.
 5. The heat equalizer according to claim 1,wherein a fin body is formed at an outer surface of said heater housingtube.
 6. The heat equalizer according to claim 1, wherein a boilingpromoter is placed at an outer surface of said heater housing tube.